EP 274 256 discloses a dosing device for dispensing liquid from a container, comprising an outlet passage for the liquid and an obturator adapted to be driven to block the outlet passage, once a quantity of liquid has been dispensed, by a restricted flow of liquid from the container into a space behind the obturator in a chamber in which the obturator is movable. A part of the device for defining the chamber comprises a movable wall portion adapted to take a first position, when liquid is being dispensed, in which access to said space behind the obturator is through a small aperture so as to provide a restriction of flow, or a second position in which there is a substantially larger aperture for liquid behind the obturator to fall back down in the container after dispensing. In one disclosed embodiment the chamber is defined by a cylinder and the obturator is constituted by a piston moveable in the cylinder. The moveable wall portion is constituted by a moveable plate that is integrally hinged to a rear edge part of the cylinder.
The moveable plate of the known dosing device of EP 274 256 hangs open when the container is in an upright position. When the container is turned upside down without immediately squeezing the container, the plate will in some events not move quickly enough to closing position whereby liquid will initially be able to flow in the space behind the piston through the large aperture instead of through the small aperture. This influences the timing of the dosing device and thus influences the dose that is dispensed. Consequently, the known dosing device does not provide consistent dosing. Another disadvantage is that the moveable plate does not open sufficiently when the container is not brought back to the upright position first. Thereby, quick successive dispensing of the same doses without bringing the container to the upright position first, is virtually impossible with the known dosing device.
The present invention has for an object to provide a dosing device that provides consistent dosing of liquid from the container.